Raising Entire Mast for Boom Clearance - Page 2 - SailNet Community
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post #11 of 19 Old 01-14-2018
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Re: Raising Entire Mast for Boom Clearance

Reminds me of the folks who put a reliable Chevy engine in their old Jaguar instead of the crap it came with. And then they find out, no one wants to hear about it at resale time.
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post #12 of 19 Old 01-14-2018
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Re: Raising Entire Mast for Boom Clearance

You are not even going to notice the difference. 12" one way or the other on a 45' mast. With the mast 12" higher you may find that you have to reef a bit earlier, instead of reefing at 15 knots you may have to start reefing when it gets to 14.5 knots. you may also find that in light air it performs better. many boats are maid with different rigs on the same hull. many build a standard rig and a tall rig. some make the same boat with fractional or masthead rig. many boats are built with a rig that is optimized for the racing rating system that the will race in. my current boat can be built wth four different rig configurations on the same hull all with in 12" in mast length and the boats all seem to sail the same. one of the configurations has the boom 24" shorter and sails better in heavy air.

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post #13 of 19 Old 01-14-2018 Thread Starter
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Re: Raising Entire Mast for Boom Clearance

Some good input here. Consulting the designer is not possible, but I have planned to consult an architect, this posting was a precursor to that to see if I had missed anything glaring OR to see if anyone had done a similar modification or air draft height increase with feedback on change in characteristics. I'm in agreement with Overbored in that many vessels come with the tall rig option and most do not alter the hull or ballast to compensate. Of course there is a performance difference but I have a feeling that shifting the main spar 12" higher isn't going to amount to much. This does not mean I've made my mind up or only want to hear opinions that support this idea. In terms of affecting resale Im really not concerned. Ive yet to meet anyone who owns or is selling a 70s vintage vessel who has much info (or interest) on the original design parameters, let alone confirmed them with a tape measure. If I was altering the rig height to make it an ICW bridge issue than yeah, thats a problem. In terms of finding another vessel, well, not many have a boom clearance of over 6'4" so I'm trying to make this concept work on a vessel I like everything else about - doing my due diligence before making an offer I know will be accepted. If anyone has any experience in this topic than please chime in. I'll be speaking with an architect in the next day or two and will update this posting with his/her opinion in case it can help someone else.
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post #14 of 19 Old 01-15-2018
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Re: Raising Entire Mast for Boom Clearance

Raising the mast a foot and ending up with a structurally sound solution is no small feat. I would advise you not to do it for a variety of reasons, but it sounds like you have your mind made up.

Some of the reasons not to do this are that the geometry of the rigging changes with the net result that you may need to replace the genoa or move or add jib sheet lead tracks further aft which in turn may require adding lead blocks to the winches. This is because the combination of change in angle of the forestay and your decision to fly the genoa higher will move the lead block quite far aft. You will also need to move the spreaders and maybe the chain plates.

Raising the height of the mast and sails a foot will be quite noticable to the way the boat feels and sails. The boat will heel more, roll more, pitch more, and need to be reefed a lot sooner.

There is a huge side force on a mast step. Designing and building mast step that is a able to resist this over turning force would be very difficult in the confined space in the bilge. I would probably only raise the mast step a few inches at most, and then splice onto the mast an extension for the rest of the height you are looking for.

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post #15 of 19 Old 01-15-2018
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Re: Raising Entire Mast for Boom Clearance

Another option would be to leave everything as is except have the sail cut to move the clew up as much as you need. You'll lose less sail area than raising the gooseneck, leave the rig intact as designed. On the downside it may look a bit odd, and you may need to lengthen your mainsheet to get the same range.

FWIW....
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Re: Raising Entire Mast for Boom Clearance

Consider pitching the boom up. Modifying the sail would take an afternoon with mama's Singer and some odds and ends from Sailrite. Or how about raising the boom, clipping the headboard and making a gaff-battened sail? Still, not a bid deal. A weekend and some parts.
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post #17 of 19 Old 01-16-2018
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Re: Raising Entire Mast for Boom Clearance

This may be a dumb question, given my complete lack of knowledge, skill and experience in this area. Couldnít you merely modify the sail and running rigging to raise the aft end of the boom by a foot?
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Re: Raising Entire Mast for Boom Clearance

Quote:
Originally Posted by Knot Again View Post
This may be a dumb question, given my complete lack of knowledge, skill and experience in this area. Couldnít you merely modify the sail and running rigging to raise the aft end of the boom by a foot?

That's what I was sayin'!
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post #19 of 19 Old 01-16-2018
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Re: Raising Entire Mast for Boom Clearance

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Originally Posted by DonScribner View Post
That's what I was sayin'!
.... and I was sayin' just before you

Ron

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".. there is much you could do at sea with common sense.. and very little you could do without it.."
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